Vania



Patented Mer. 8, 1898.

A. 08.7M0TT e A. 0. EDGAR. RELIEF DEVICE FOR HOT WATER HEATERS No. 000,440.

FIC-2.1,

(No Model.)

Ninn STATES PATENT muon.

ABRAM C. MOTT AND ANDREV C. EDGAR, OF PHILADELPHIA, PENNSYL- VANIA; SAID EDGAR ASSIGNOR TO SAID MOTT.

HELlEF DEVICE FOR HOT-WATER HEATERS.

SPECIFICATION forming part of Letters Patent NO. 600,440, dated March 8, 1898. Application filed August 25, 1897. Serial No. 649,484. (No model.)

T CLZ whom, t may] concern:

Be it known that we, ABRAM C. MOTT and ANDREW C. EDG-AR, citizens of the United States, and residents of Philadelphia, Penn- Sylvania, have invented certain Improvements in Relief Devices for Hot-Water Heating Systems, of which the following is a speciication.

The object of our invention is to provide a 1o hot-water heating systemin which the Water may he maintained under any desired degree of pressure, but from which a free escape of the surplus water is permitted as soon as such predetermined pressure is exceeded, this re- I 5 sult, moreover, being attained without the use ot' weighted valves or other mechanical devices liable to become inoperative through neglect, so as to cause explosions or other accidents due to excessive pressure.

2o In the accompanying drawings, Figure l is a diagram illustrating a hot-water heating system provided with pressure-regulating relief devices in accordance with our invention; and Fig. 2 is a View, on alarger scale, of such pressure regulating and relief devices.

Since the inception of the plan of heating houses by means of hot water, engineers have recognized the fact that if the water could be maintained at a high temperature it would be 3o more valuable than steam as a heating medium on account of its constancy, as with water the heat is not subject to rapid or extreme fluctuation, whereas if steam is used and the temperature of the water in the boiler falls below the boiling-point the steam condenses in the radiators and its place is supplied with air, which must be expelled when steam is again generated before the radiator can be reheated, and in practice it very often 4o happens that the air is not entirely expelled and the heating-surface of the radiator is reduced to a corresponding extent.

Various methods have been adopted for maintaining a high temperature in the water used for heating purposes, one plan being to extend above the expansion-tank, which in all hot-waterheating systems is used at the highest point of the system, a pipe filled with water, each twenty-eight inches of water in this pipe 5o representing one pound of pressure at its base and raising the boiling-point ofthe water about two and a half degrees; but of course in ordinary houses the use of such a hydrostatic column above the expansion-tank is wholly inadmissible. In modern hot-waterpressure systems, therefore, it is customary to provide the escape-pipe of the expansiontank with a safety-valve weighted to the desired pressure, (which is rarely, if ever, more than ten pounds;) but the danger of this is 6o apparent, as a safety-valve in the hands of ignorant users may remain closed for such a length of time as to cause it to rust fast or otherwise become inoperative. Hence when the occasion arises for it to perform its intended duty it is incapable of doing so, and an explosion or other accident due to excessive pressure results. With the view of overcoming these objections we have devised our invention, which We will now proceed to de- 7o scribe.

l represents an ordinary expansion-tank occupying a position at the highest point of the system and communicating with the upper end of the supply-main, so that as the water is expanded by heat it will iow into this tank. Extending from one side of the tank is a pipe 2, which communicates with an upright pipe 3, having at the top any suitable form of vacuum-valve 4that is to say, 8o a valve which will open and permit an inflow of air as soon as a partial vacuum is formed in the pipe 3. The lower end of the pipe 3 is connected by a bend 5 to an upright pipe 6, which at the upper end communicates through a bent neck 7 with a vessel 9 of substantially cylindrical form, said vessel having at one side an outlet-neck l0, which communicates with a waste-pipe 1l.

In preparing this device for operation the 9o lower portion of the pipe 3, the lower portion of the pipe 6, and the bend 5 are filled with mercury, which may be conveniently introduced through an opening in the top of the vessel 9, this opening being then closed by means of a suitable cap or cover l2. This body of mercury thus constitutes a seal, and it will be evident that no water can be discharged from the expansion-tank l until this seal is first displaced. As the pressure rises roo the mercury is gradually forced from the lower portion of the pipe 3 and bend 5 into the pipe 6, and as soon as the pressure of water is sufiicient to overcome the weight of the Acolumn of mercury maintained in said pipe the latter is thrown up into the chamber in the vessel 9 and the water passes through said chamber and escapes through the discharge-pipe 11, the mercury again flowing back into the pipe 6 as soon as the pressure ofthe water is sufficiently reduced. Y

The object of making the vessel 9 of cylindrical form is to prevent the carrying of mercury away with the escaping current of water, since it will be noted that when the mercury is forced into the chamber contained in the vessel 9 it follows the curved interior of the same and is directed downward past the mouth of the outlet-neck 10, so as to accumulate in the lower portion of the chamber 9 in readiness to flow back into the pipe 6 as soon as the pressure of the water in the system is properly reduced.

It will be evident therefore that by maini taining a column of mercury of the proper height as a seal for the expansion vessel 1 any desired pressure of Water in the system may be maintained and the desired high temperature of the water thus rendered possible, while at the same time there is no possibility of accident such as is likely to result from the use of a mechanical valve, since the mercury seal is automatic in its action and needs no attention in order to maintain it constantly in operative condition.

As the one-inch column of mercury gives a pressure equal to a fourteen-inch column of Water, it will be evident that the desired pressure of Water in theheating system can by the use of the mercury column be maintained Without increasing the size or height of the sealing device to an extent which will preclude its use in any ordinary dwelling.

The bend 5 is provided with a petcock 13 or other suitable form of escape-valve, so that the mercury and water which may be contained in the pipes 3 and 6 and vessel 9 may be drained off when the heating system is not in use or when for any otherreason such removal becomes advisable.

While We prefer to use our pressure regulating and relieving device in connection with the expansion-tank, it will be evident that it may, witho ut departing from the essential features of oui` invention, be connected, if desired, directly with the upper end of the supply-main, or the device may be used in connection with a steam heating-boiler in place of a safety-valve.

Having thus described our invention, we claim and desire to secure by Letters Patent- 1. The combination of an escape-pipe of a water heating system or steam-boiler, with a mercury seal for closing said pipe, and a casing containing a chamber into which the mercury is forced when the predetermined pressure is exceeded, said chamber having an outlet through which the excess of water or steam can escape, and having such communication with the seal that the mercury will automatically return to the latter when the pressure falls.

2. The combination of the escape-pipe of a hot-Water heating system or steam-boiler,with a mercury seal for closing said pipe, and a vessel of curved section communicating with said mercury seal and with an outlet-pipe, the connection with the seal being such that as the mercury is forced into the vessel, it is caused to follow the curved wall of the same, and prevent its escape through the outlet.

3. The combination of the escape-pipe of a hot-water heating system, with a mercury seal for closing said pipe, and a vacuum-valve for admitting air to the pipe on the pressure side of the seal, when the Water falls therein.

4L. The combination of the expansion-chainber of a hot-Water heating system, with an escape-pipe leading therefrom, a mercury seal for said pipe, a casing containing a chamber into which the mercury is forced when the` predetermined pressure is exceeded, an outlet from said chamber for the surplus water, and a communication through AWhich the mercury can automatically flow back from said chamber into the seal when the pressure is reduced.

In testimony whereof we have signed our names to this specification in the presence of two subscribing Witnesses.

- ABRAM C. MOTT.

ANDREV C. EDGAR. Witnesses:

VILL. A. BARR, Jos. H. KLEIN. 

